Looking at the back, the pickups are original, but looks like someone added some nickel covers afterwards. The bridge pickup still has the HFS label (Hof Fat Screams), and the neck pickup looks like PRS as well, and you can see fading where the VB (Vintage Bass) label would have been. They often fall off after so many years.
Markings indicate the finish (Vintage Sunburst, my favorite), WT for Wide Thin neck (also my favorite), RF for Rosewood Fretboard and the serial number, which matches the neck plate. The rest are usually notes and initials from the craftsmen, and looks like the guitar was made by or for Ben Rivera - could be a custom order (workers typically put only their first name or initials). Manufacture date looks like May 20th, 1991.
All seems in order - it's probably a matter of preference if you want to keep the covers or not but the pickups are original. I still think the 3-way is not original (since I think PRS used different wiring and a right-angle toggle) but it is no big deal if you want to have it restored to the 5-way. Looks like you got a very nice find - enjoy!
Edit - I googled Ben Rivera and PRS and it turns out he was a PRS employee in 1991. The Internet has no secrets